1. Field of the Invention
The present invention relates to a headgear frame apparatus attached removably to the drive frame of a sewing machine for clamping a headgear.
2. Description of Related Art
As shown in FIGS. 6 and 7, a headgear frame apparatus 105 of the prior art is provided with: a headgear frame 100 for clamping a headgear 1; a rotary drive frame 106 for fitting the headgear frame 100 replaceably on the sewing machine side; a support frame 109 for supporting the rotary drive frame 106 turnably; and a guide plate 110 fixed on the support frame 109 and extending to the side of a cylindrical bed 111 of the sewing machine.
When this headgear frame apparatus 105 is to be attached to a drive frame 112 of the sewing machine, a mounting bracket 113 is fixed on the upper face of the drive frame 112. On the back face of the bracket 113, there is mounted a rotationally driving slide rail 114 having a rail groove 114a, to which the support frame 109 is connected through a bearing roller 115.
In the headgear frame apparatus 105 thus far described, it is simple to attach the support frame 109, however a clearance 116 never fails to be formed between the rail groove 114a and the bearing roller 115 so that it causes a longitudinal looseness exerting an adverse affect on the embroidering quality. At a high speed run (e.g., at 750 rpm), moreover, the support frame 109 or the headgear frame 100 vibrates to cause a frequent breakage of the needle or an unsatisfactory embroidery finish.
Therefore, the present inventors have proposed an improvement (Japanese Patent Application No. 11-106172, although not opened at the time of this application), as shown in FIG. 8. In this proposal, the support frame 109 is constructed of a front member 205 positioned on the front side of the drive frame 112, and a rear member 206 positioned on the rear side of the drive frame 112. Moreover, a front bearing roller 208 mounted rotatably on the front member 205 and a rear bearing roller 207 mounted rotatably on the rear member 206 clamp the drive frame 112 longitudinally, and the front member 205 and the rear member 206 are jointed by inserted and fastened a joint screw 210, as threaded in one of them, into a U-shaped groove 209 formed in the other. This structure has succeeded in eliminating the looseness of the support frame 109 or the headgear frame 100 to solve the above-specified problem.
When the headgear frame apparatus 105 of the proposal is to be attached to the drive frame 1112, however, the operator is required to manipulate the rear member 206 to below or backward of the drive frame 112 and to join the front member 205 and the rear member 206 while applying the rear bearing roller 208 to the rear face of the drive frame 112. This is a work at a rather backward deep position, as viewed from the front of the headgear frame apparatus 105 while groping, thus leaving a problem of poor workability.
An object of the present invention is to provide a headgear frame apparatus which can solve the above-specified problems and can be attached easily without any looseness to the drive frame of a sewing machine.
According to the present invention, there is provided a headgear frame apparatus adapted to be removably attached to a drive frame adapted to be driven transversely and longitudinally of a sewing machine and extending transversely, comprising: a mounting base frame attached removably to the front side of the drive frame and adapted to be driven transversely and longitudinally together with the drive frame; a support frame connected to the mounting base frame such that it is driven with the mounting base frame longitudinally but not transversely; a rotary frame supported rotatably on the support frame; a headgear frame fitted removably on the rotary frame for clamping a headgear; and a rotation converting member interposed between the mounting base frame and the rotary frame for converting the transverse motions of the mounting base frame into rotations of the rotary frame, wherein the mounting base frame includes a guide face confronting the drive frame front face of the drive frame from the front and extending transversely, and wherein one or more front bearing roller for abutting against the guide face and one or more rear bearing roller for abutting against the drive frame front face are rotatably borne on the support frame respectively.
It is preferred that there is further comprised roller span adjusting means for holding the front bearing roller and the rear bearing roller with their pivot pins having a longitudinal span expanded, to bring the front bearing roller and the rear bearing roller individually into abutment without any looseness against the guide face and the drive frame front face.
The roller span adjusting means should not be limited to a specific structure but can be exemplified by the following modes i) and ii).
i) The mode in which the roller span adjusting means includes: an adjusting lever supporting the pivot pin of the front bearing roller or the rear bearing roller and hinged turnably to the support frame; and lever holding members for stopping and holding the adjusting lever at the rotation adjusted position on the support frame. It is preferred that the adjusting lever is so disposed that it can be manipulated by an operator from the front of the headgear frame apparatus.
ii) The mode in which the roller span adjusting means is one or more spring for urging both or one of the pivot pins of the front bearing roller and the rear bearing roller in a direction to expand the longitudinal span of the both pivot pins.
There can be exemplified the mode, in which one of the front bearing roller and the rear bearing roller is provided by one whereas the other is provided by two or more; or the mode in which both of them are provided by two or more respectively.
Further objects of this invention will become evident upon an understanding of the illustrative embodiments described below. Various advantages not specifically referred to herein but within the scope of the instant invention will occur to one skilled in the art upon practice of the presently disclosed invention. The following examples and embodiments are illustrative and not seen to limit the scope of the invention.